If the ductwork was sized for a gas furnace and air conditioning , it will be undersized for a heat pump .

I bought a house that will need a full gut renovation I am just curious to see how much it has cost to put in a furnace, central air unit and full duct work.

Ductwork under house obviously has holes.

I'll be closing on a triplex soon and 2 of the 3 units share duct work (furnace/ac).

My quotes from 3 contractors on each house ranged from $12,000-15,000... these houses were two story with no ductwork.

We have done ALL the work ourselves except for finishing the drywall.I will do a whole RENO thread once its done, but here is just a quick overview of what we have done.Whole new Heat and Air unit, switched to gas, and moved duct work from under the house to the attic.

You have to know that drain lines take precedence and tell the other trades that "Yes, you need to move your duct work because it is in the way of my drain line" Make your electrician find another way to run his conduit and keep the peace. 

All the ductwork is new.

@Justin HodgesMight consider how much load this is going to put on the cooling system, and ductwork.

Average quotes for new HVAC have been coming in around 15-20k for furnace, AC, and all new ductwork along with remediation and removal of the old furnace.